It is desirable to provide improved polymeric films which conform better to irregular surfaces to which the film may be applied for example when used as a facestock in the label or graphic art fields. Previous films which were highly conformable were often unsuitable for use as labels. To achieve improved levels of conformability required unacceptable compromises on other film properties also desired or necessary in a label. For example conformable labels had unacceptable optical properties e.g. insufficient clarity for a transparent label to achieve a “no-label look”.
Certain multi-layer polypropylene films which comprise layers of other copolymers are known.
For example, WO 00/54968 (Mobil) describes a multi-layer film with a core layer of syndiotactic polypropylene. Other layers of the film (such as a skin layer and/or a layer adjacent to the core layer of this film) may comprise ethylene copolymers and/or terpolymers containing co-monomers of propylene and butene-1. These films are stated to have advantageous barrier properties for example, for packaging applications. They are also described as having “remarkable toughness and resistance to deformation” which teaches directly away from use of such films on conformable substrates.